a. Field of Invention
The invention relates generally to vehicle lighting systems, and, more particularly, to a vehicle headliner mounted center high mount stop lamp (CHMSL) with improved manufacturing, assembly and operational characteristics.
b. Description of Related Art
Vehicle headliner mounted center high mount stop lamps (CHMSLs) are well known in the art and are typically used in a variety of vehicles for providing a secondary means of warning or signaling when a vehicle's brakes are applied. Typically a CHMSL is mounted at or behind the vehicle rear window. For example, referring to FIG. 1A, conventional “end item” CHMSL designs, such as CHMSL 10, include a CHMSL which is manufactured separately as a unit and thereafter installed generally high and aft in the vehicle. A headliner 12 is then disposed over the CHMSL in a separate assembly step. While such CHMSL designs are acceptable in vehicles such as sport-utility vehicles, vans and other large vehicles, in cars, especially in coupes, installation of an end item CHMSL is comparably difficult due to the ergonomic factors of such vehicles which require an assembly operator to gain access to the assembly location in an often cramped environment. This is because the center, aft roof area in an automobile is difficult to access and reach by an assembly or a service operator, especially in a fast-paced vehicle assembly operation.
In order to address such manufacturing concerns associated with end item CHMSL designs, a variety of “part-in-assembly” (PIA) CHMSL designs have been proposed. Referring to FIG. 1B, an exemplary PIA headliner mounted CHMSL 14 is illustrated. Such PIA CHMSL designs eliminate the need for an assembly operator to separately install the CHMSL. Thus, while such PIA CHMSLs solve a variety of ergonomic and manufacturing concerns, current designs for PIA headliner mounted CHMSLs are nevertheless expensive because they require additional components for mounting and servicing the CHMSLs in a vehicle. For example, current PIA headliner mounted CHMSL designs, such as CHMSL 14 of FIG. 1B, have an expensive Class “A” cover panel 16 that is usually color keyed with the vehicle interior. This color keyed featured adds additional cost and complexity to the CHMSL design. The CHMSL bulbs (not shown) can only be serviced by removing panel 16. Additionally, current PIA headliner mounted CHMSL designs, such as CHMSL 14, have an expensive mounting bracket 18 that his hidden from view and supports attachment of the CHMSL to the vehicle body sheet metal 20. Bracket 18 must also be rigid for providing adequate support and therefore adds additional cost to the overall PIA CHMSL component. Further, current PIA headliner mounted CHMSL designs, such as CHMSL 14, typically require a mold on rubber seal (not shown) for eliminating reflected light from the backlight when the brake pedal is depressed. This mold on seal adds further cost to the overall PIA CHMSL component and can further complicate production tooling. Yet further, current headliner mounted CHMSLs (PIA as well as end item) require additional assembly plant labor and effort, in that existing designs are sensitive to tolerances and build variation due to the requirement for multiple components which create fit and finish concerns. These factors therefore limit use of existing interior roof mounted CHMSLs for luxury and other high-end automobiles, with exterior roof mounted CHMSLs being used for less expensive automobile designs.
Accordingly, there remains a need for a vehicle headliner mounted CHMSL, which is economical to manufacture, install and service, as compared to existing end item or PIA CHMSL designs, and is further robust in design for long term use in a variety of vehicles, including, SUVs, sedans, coupes and sports cars. There also remains a need for a CHMSL design which reduces design and tooling costs, and which further meets automotive fit and tolerance requirements for such components.